Tell me what the symbol is for arithmetic sum?

I know a geometric sum (factorial) is an explanation point, what's the symbol for an arithmetic sum?

x??? = x + (x-1) + (x-2) + ... + 1

I believe you are talking about upper-case sigma.

Σ

Although, I'm not entirely sure. I used that two years ago.

Yes, Σ is right. So you'd represent x + (x-1) + (x-2) + ... + 1 as
http://img388.imageshack.us/img388/2...etexcgiym1.gif

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Originally Posted by •Neko•

Yes, Σ is right. So you'd represent x + (x-1) + (x-2) + ... + 1 as
http://img388.imageshack.us/img388/2...etexcgiym1.gif

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Dude, I sat here last night for 15 minutes trying to remeber this shit from college. Screw it. :morecrying:

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Originally Posted by Howie

Dude, I sat here last night for 15 minutes trying to remeber this shit from college. Screw it. :morecrying:

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I wanna be online when you get 10000 teehee.

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Originally Posted by ClouD

I wanna be online when you get 10000 teehee.

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College didn't teach me how to count that high either. :(

Shit I'm getting close aren't I ?
I do Roman numerals though -X :banana:

Quote:

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Originally Posted by Howie

Dude, I sat here last night for 15 minutes trying to remeber this shit from college. Screw it. :morecrying:

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Hehe, sorry Howie. I was studying Maths a few minutes before I made that post, so it inspired me to do so. :P